Refrigerator evaporator with defrosting means



REFRIGERATOR EVAPORATOR WITH DEFROSTJ'J NG MEANS 5 Sheets-Sheet 1 Filed Dec. 29, 1952 I lull Dec. 11, 1956 SI J. WILLIAMS, JR

REFRIGERATOR EVAPORATOR WITH DEFROSTING MEANS 5 Sheets-Sheet 2 Filed Dec. 29, 1952 'amso? ill:

1956 51 J. WILLIAMS, JR 2,773,363

REFRIGERATOR EVAPORATOR WITH DEFROSTING MEANS Filed Dec. 29, 1952 s Sheet-Sheet 3 United States Patent" REFRIGERATOR EVAPORATOR WITH DEFROSTING MEANS Si 3. Williams, Jr.., Evansville, Ind., assignor, by mesne assignments, to Whirlpool-Seeger Corporation, a corporation of Delaware Application December 29, 1952, Serial No. 328,449

9 Claims. (Cl. 62126) frigerator evaporator which may be rapidly and efficiently defrosted through the use of hot gaseous refrigerant.

It is a feature of this invention that means are pro vided for the accumulation of liquid refrigerant in some portion of the evaporator, which portion is in thermal contact with heater means.

it is another feature of this invention that a construction is provided which will cause the hot gaseous refrigerant to flow in a predetermined direction through the evaporator to complete a circuit throughout the length of the evaporator tubings.

Other objects and features of the invention will be apparent upon a perusal of the following specification and drawings, of which:

Figure l is a perspective view of one embodiment of the invention;

Figure 2 is a perspective of another embodiment of the invention;

Figure 3 is a front plan view of the embodiment shown in Figure 2;

Figure 4 is an enlarged portion of part of the embodiment shown in Figures 2 and 3;

Figure 5 is a perspective view of another embodiment of the invention;

Figure 6 is a perspective View of another embodiment of the invention; and

Figure 7 is a side plan view of the embodiment shown in Figure 6.

The present embodiments are the preferred embodiments but it is to be understood that changes can be made in the present embodiments by one skilled in the art without departing from the spirit and scope of this invention.

For a description of the invention reference is first made to Figure 1. The embodiment shown therein comprises a base portion 2 and a rear wall portion 3 attached thereto. Extending in a horizontal plane from the rear wall 3 are two shelves. Formed in the base 2, the rear wall 3, and the shelves 4 and 5 is a length of serpentine tubing 6. The evaporator with this tubing may be constructed in any manner well known in the art, such as by welding or brazing the tubing to the plane surfaces of the evaporator or by forming the evaporator of two sheets bonded together with the configurations of the various tubings stamped therein. A small chamber 7 is formed in the rear wall substantially .at the top thereof. One end of the serpentine tubing 6 is connected to one end of the chamber 7. An inlet tube 8 is mounted to project into the chamber 7 some distance from the point of en- 2,773,363 Patented Dec. 11, 1956 try of the inlet tube 8. The other end of the serpentine tubing 6 is connected to one end of .a reservoir or accumulator 9 which is formed in the rear wall substantially at the top thereof. An outlet tube 10 is connected to the other end of the reservoir 9, thus when the evaporator is connected in a conventional refrigerator (not shown) liquid refrigerant will flow from the inlet tube 8 into the chamber '7, through a portion of the serpentine tubing 6 in the rear wall 3, through a portion of the serpentine tubing 6 in the shelf 5, through a portion of the serpentine tubing 6 in the rear wall 3, through a portion of the serpentine tubing 6 in the shelf 4, through a portion of the serpentine tubing in the rear wall 3, through a portion of the serpentine tubing 6 in the base 2, through a portion of the serpentine tubing 6 in the rear wall 3 to the reservoir 9. A length of tubing 11 is also provided. One end of the tubing 11 is connected to the serpentine tubing 6 at the junction 12. A portion of the other end of the tubing 11 is formed in the rear wall 3 and is connected to the chamber 7 between the point of entry of the inlet tube 3 and the end of the inlet tube 8. The remainder of the tubing 11 depends from the rear wall 3 below the base 2 and one portion 13 of the tubing 11 is inclined in a generally downward direction. To the portion 13 of the tubing 11, a heater 14 is mounted in good thermal contact. The heater 14 may be of any type well known in the art such as an electrical heating element.

To describe the operation of the embodiment shown in Figure 1, reference is made thereto. When the evaporator is connected in a conventional refrigerator (not shown), operating on the refrigeration cycle, liquid refrigerant will proceed through the serpentine tubing 6 as described above. Additionally, liquid. refrigerant upon reaching the junction 12 will flow downward into the tubing 11 and upward through the portion 13 of the tubing 11. Substantially no liquid refrigerant will flow from the inlet tube 8 directly into the tubing 11 since the end of the inlet tube 8 extends into the chamber 7 beyond the opening of the tubing 11 connected to the chamber 7. Furthermore, the chamber 7 is inclined in a generally downward direction so that the end of the inlet tube 8 is below the opening of the tubing 11. Therefore, as the evaporator operates during a normal refrigeration cycle the tubing 11 Will stand full of the liquid refrigerant. Now when the evaporator is to be defrosted, the normal refrigeration cycle is stopped, and the heater 14 is energized. The heater 14 will heat the portion 13 of the tubing 11, and when the liquid refrigerant disposed therein has been heated to the point of its latent heat of vaporization, the liquid refrigerant will assume a hot gaseous state. The hot gases will then proceed in a generally upward direction along the portion 13 of the tubing 11, up

the remainder of the tubing 11, through the chamber 7, i

through the various oonvolutions of the serpentine tubing 6 to the junction 12. The hot gases as they flow through the various oonvolutions of the serpentine tubing 6 will force any liquid refrigerant therein to the junction l2, and this liquid refrigerant will then proceed downward into the tubing lit. As the hot gases strike the cold surfaces of the evaporator they condense to a liquid, giving up latent heat of vaporization to warm the evaporator and to melt the frost. Substantially all of the portions of the evaporator will then be heated to cause any frost thereon to be melted.

For a description of the embodiment shown in Figures 2-4, reference is made thereto. The embodiment shown therein comprises a base 20 and a rear Wall 21 attached thereto. and 23 are mounted as can easily be seen in Figures 2 and 3. This embodiment further includes specific reservoirs and tubings which may be welded to or formed by stampings in the various sheets of the evaporator as To the rear Wall 21, two shelves 22 i described previously in regard to Figure l. Specifically, serpentine tubing 24 is provided. The various convolutions of the serpentine tubing 2 may easily be seen in Figures 2 and 3 as extending from the substantially upper portion of the rear wall 21, sloping downward to and through the shelf 23 through the rear wall 21 to and through the shelf 22 to a reservoir 25, from the reservoir 25 to the base 20, through the base to the rear wall 21, upwardly through the rear wall 21 to the reservoir 26. The reservoirs and 26 are longitudinal in shape, as can easily be seen in Figures 2 and 3, and positioned in the rear wall 21 in oppositely sloping directions. An outlet tube 27 is connected to the upper end of the reservoir 26. An inlet tube 28 extends some distance into a chamber 29. To the opposite end of the chamber 29?, the other end of the serpentine tubing 24 is connected. The details of the chamber 29, which is very similar to the chamber 7 of Figure 1, may easily be seen in Figure 4. A joining tube 30 is connected to the lower end of the reservoir 26 and the chamber 29 between the point of entry into the chamber 29 of the inlet tube 28 and the end of the inlet tube 28. The other end of the serpentine tubing 24 is connected to the reservoir 26 at a point between the joining tube 31 and the outlet tube 27. The connections of the reservoir 25 may be easily seen in Figures 2 and 3. The upper end of the reservoir 25 is connected to that portion of the serpentine tubing 24 which leads to the chamber 29. The lower end of the reservoir 25 is connected to that portion of the serpentine tubing 24 which leads to the reservoir 26. Between the lower end of the reservoir 25 and the connection of the serpentine tubing 24 to the reservoir 26 and depending from the underside of the base 2i), a loop 31 of the serpentine tubing 24 is provided. In thermal contact with the depending portion of the serpentine tubing 24 or the loop 31 is a heater 32. This heater 32 may be of any type well known in the art, such as an electrical heater.

To describe the operation of the embodiment shown in Figures 2-4, reference is made thereto. When the evaporator is connected in a conventional refrigerator (not shown) which is operating on a refrigeration cycle, liquid refrigerant will enter the inlet tube 28 and flow through the chamber 29. Since the chamber 25 has a downward slope as seen in Figure 3 and since the joining tube 31 is positioned rearwardly from the end of the inlet tube 28, substantially no refrigerant will flow into the joining tube 3d. The liquid refrigerant will flow from the chamber 29 through the serpentine tubing 24 to the reservoir 26. As the liquid refrigerant flows along this path a substantial amount of liquid refrigerant will accumulate in the reservoir 25, and the liquid refrigerant will also stand in the loop 31. Now when it is desired to defrost the evaporator, the refrigeration cycle is stopped and the heater 32 is energized. As described previously, the heater 32 will cause the liquid refrigerant within the tubing with which it is in thermal contact, in this embodiment the loop 31, to assume a hot gaseous state. Since the volume of liquid refrigerant disposed within the reservoir 25 will be much greater than that disposed in the tubing 33, leading from the loop 31 to the reservoir 26, the hot gases produced will first proceed through the tubing 33 positioned between the loop 31 and the reservoir 26. Thehot gases will enter the reservoir 26 and will then proceed through the joining tube 30. Of course, any liquid refrigerant disposed therein will flow downward through the joining tube 3%. The hot gases and the liquid refrigerant will proceed through the chamber 29 and into the remainder of the serpentine tubing 24. The hot gases and liquid refrigerant will then flow through the remainder of the serpentine tubing 24 into the reservoir 25 to complete the cycle. Thus, substantially all of the evaporator surfaces will be efficiently heated to melt any frost which has accumulated thereon. When defrost ing is completed, the refrigeration cycle may again be started and the liquid refrigerant will flow as previously described for the refrigeration cycle.

For a description of the embodiment shown in Figure 5, reference is made thereto. A horizontal base 44B is provided to which a vertical rear wall 41 is attached. Two reservoirs 42 and 43 and the serpentine tubing 44 are provided in cooperation with the rear wall 41 and the base 40, and as previously described these elements may either be welded to the rear wall 41 and the base 40 or they may be stamped into two sheets which are then bonded together to form the rear wall 41 and the base 4'!) with these elements formed therein. The longitudinal reservoir 42 is disposed in a horizontal direction substantially at the top of the rear wall 41. The longitudinal reservoir 43 is also positioned in a horizontal direction in the rear wall 41 and is spaced some distance from and below the reservoir 42. An outlet tube 45 is connected to one end of the reservoir 42. A joining tube 46 is connected to one end of the reservoir 4-3, and to the other end of the reservoir 42. The serpentine tubing 44 is positioned in the rear wall 41 and the base 40 and as can easily be seen in Figure 5, each convolution of the ser-- pentine tubing 44 is partially disposed in the rear wall 41 and partially disposed in the base 40. One end of serpentine tubing 44 is connected to the other end of the reservoir 43 and the other end of the serpentine tubing 44- is connected to the other end of the reservoir 42. An inlet tube 4-7 is disposed in the rear wall 41 and is connected to the one end of the reservoir 43 and extends some distance into the reservoir 43. A heater 43 is mounted in thermal contact with one vertical portion 49 of one convolution of the serpentine tubing 44 disposed in the rear wall 41, as can easily be seen in Figure 5. As described previously, the heater .8 can be of any type well known in the art.

To describe the operation of the embodiment shown in Figure 5, reference is made thereto. When the evap orator is connected in a conventional refrigerator (not shown) which is operating on the refrigeration cycle, liquid refrigerant flowing in the inlet tube 4'7 will enter the reservoir 43. The liquid refrigerant will then flow the length of the reservoir 43 and will then flow downward into the end of the serpentine tubing 44 connected thereto. No liquid refrigerant will enter the joining tube 46 from the inlet tube 47, since the joining tube 46 is connected to the reservoir 43 at the top thereof, and since the joining tube 46 is disposed rearwardly from the tip of the inlet tube 47. The liquid refrigerant will then flow through the various convolutions of the serpentine tubing 44 to the reservoir 4-2. Some liquid refrigerant will be maintained in the portion 49 of the serpentine tubing 4-4. Now when it is desired to defrost the evaporator, the refrigeration cycle is stopped and the heater 48 is energized. This will cause the liquid refrigerant disposed within the portion 49 to boil, and the hot gases produced thereby will proceed upwardly through the remainder of the portion 49 forcing the liquid refrigerant disposed forwardly of that portion to flow through the serpentine tubing 44 into the reservoir 42. As the hot gases proceed through the serpentine tubing 44 the liquid refrigerant forced into the reservoir 42 will flow through the joining tube 46 into the reservoir 43 and from the reservoir 43 into the remainder of the serpentine tubing 44 back to the portion 49 to complete the cycle. As may easily be seen, this manner of operation assures a continuous supply of liquid refrigerant to the portion 49 for heating by the heater 48. The evaporator will then be effectively defrosted by the hot gases throughout the various portions thereof and upon a completion of the defrosting cycle the evaporator may again be operated during the refrigeration cycle.

For a detailed description of the embodiment shown in Figures 6 and 7, reference is made thereto. A horizontally disposed base 50 is providedv with a vertically disposed rear wall 51 attached thereto. Cooperating with the rear waiter arid the baseso is a reservoir 5-3-andtwo lengths of serpentine tubing 54 and 55. As previously described,- these elements may be welded to the rear wall 51 and the base 50 or they may be formed therein by a stamping and bonding of two sheets. One end of the serpentine tubing 55 is connected to an inlet 56. The reservoir 53 is longitudinally disposed substantially at the top of the rear wall 51. To one end of the reservoir 53 an outlet tube 57 is connected. To the other end of the reservoir 53 the other end of the serpentine tubing 55 is connected. The convolutions of the serpentine tubing 55 are distributed'throughout the area of the rear wall 51 and the base 50, as can easily be seen in Figure 6. The serpentine tubing 54 is a closed circuit and has a refrigerant disposed therein. The convolutions 0f the serpentine tubing 54 follow and are evenly spaced from the convolutions of the serpentine tubing 55, as can easily be seen in Figure 6. A portion 58 of the serpentine tubing 54 is formed to depend from the underside of the base 50, as can easily be seen in Figures 6 and 7. A heater 59 is mounted to the portion 58 of the serpentine tubing 54 in thermal contact therewith. As described previously, the heater 59 can be of any type well known in the art such as an electrical heater.

To describe the operation of the embodiment shown in Figures 6 and 7, reference is made thereto. When the evaporator is connected in a conventional refrigerator (not shown) and operated on a refrigeration cycle, liquid refrigerant will enter the serpentine tubing 55 through the inlet tube 56. The liquid refrigerant will then proceed through the convolutions of the serpentine tubing 55 to the reservoir 53; The refrigerant in the secondary system, the serpentine tubing 54, will drain into the portion 58. Now when it is desired to defrost the evaporator, the refrigeration cycle is stopped and the heater 59 isenergized. The heater 59 willthen heat the portion 58 to cause the liquid refrigerant therein to assume a hot gaseous state. The hot gases produced will then circulate throughout the convolutions of the secondary system and will thereby heat substantially all of the portions of the evaporator to melt any accumulations of frost thereon. After the evaporator has been effectively defrosted, the electrical heater 59 is deenergized, and the evaporator may then again be operated during a refrigeration cycle.

Having described the invention, what is considered new and desired to be protected by Letters Patent is:

.1. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically disposed rear wall attached thereto, a first length of serpentine tubing formed in said base and in said rear wall, a second length of tubing connected in parallel to said first length of serpentine tubing, a portion of said second length of tubing being convoluted and depending from said rear wall below said base, a section of said portion of said second length of tubing extending in a diagonally downward direction, whereby liquid refrigerant collects in said section of said portion of said second length of said tubing when said evaporator is connected in a refrigerator, heating means mounted in thermal contact with said section of said portion of said second length of tubing for heating said section to cause said liquid refrigerant to assume a hot gaseous state, said first length of serpentine tubing being convoluted so that the hot gases are projected throughout said first length of said serpentine tubing when said liquid refrigerant is heated to said hot gaseous state.

2. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically disposed rear wall attached thereto, a length of serpentine tubing formed in said base and said rear wall, the ends of said length of serpentine tubing terminating substantially at the top of said rear wall, a longitudinal chamber formed in said rear wall substantially at the top thereof, oneend of said serpentinetubing connected to one end of said chamber, an inlet tube connected to the other end of said chamber and projecting some distancce into said chamber, a second length of tubing being convoluted and partially formed in said rear wall and partially depending from said rear wall below said base, one end of said second length of tubing connected to said chamber between the end to which said inlet tube is connected and the end of said inlet tube, a section of the portion of said second length of tubing depending from said rear wall extending in a diagonally downward direction from the portion of said second length of tubing connected to said chamber, the other end of said second length of tubing connected to said first length of serpentine tubing formed in said rear wall, whereby liquid refrigerant will collect in said section of said second length of tubing when said evaporator is connected in a refrigerator, heating means mounted in thermal contact with said section of said second length of tubing for heating said section to cause said liquid refrigerant to assume a hot gaseous state, whereby the hot gases are projected upward from said section through said chamber and through said first length of serpentine tubing when said liquid refrigerant is heated to said hot gaseous state.

3. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet as claimed in claim 2, the other end of said first length of serpentine tubing connected to a reservoir formed in said rear wall substantially at the top thereof, an outlet connected to said reservoir, said one end of said first length of serpentine tubing connected to said chamber being formed in said rear wall to extend in a generally downward direction, whereby liquid refrigerant will flow from said inlet tube into said first length of serpentine tubing, through said first length of serpentine tubing and simultaneously into said second length of tubing and through said first length of serpentine tubing connected to said reservoir, when said evaporator is connected in a refrigerator.

4. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet as claimed in claim 2 a pair of shelves mounted in a horizontal plane to said rear wall, each of said shelves mounted at one vertical edge of said rear wall, said first length of said serpentine tubing further formed in said shelves.

5. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically disposed rear wall attached thereto, serpentine tubing formed in said base and said rear wall, an additional portion of said serpentine tubing being convoluted and formed to depend from the underside of said base, whereby liquid refrigerant will collect in said additional portion of said serpentine tubing when said evaporator is connected in a refrigerator, heating means mounted in thermal contact with said additional portion for heating said additional portion to cause said liquid refrigerant to assume a hot gaseous state, the other portions of said serpentine tubing shaped so that the hot gases from said additional portion are projected throughout said serpentine tubing when said refrigerant is heated to said hot gaseous state.

6. An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically disposed rear wall attached thereto, a length of serpentine tubing formed in said base and said rear wall, an additional portion of said serpentine tubing being convoluted and formed to depend from the underside of said base, the ends of said serpentine tubing terminating in said rear wall substantially at the top thereof, a longitudinal reservoir formed in said rear wall and positioned in a generally diagonally downward direction, the ends of said reservoir connected in one portion of" said serpentine tubing formed in saidrear wall, a longitudinal chamber formed in said rear wall substantially at the top thereof, one end of said serpentine tubing connected to one end of said chamber, an inlet tube extending some distance into said chamber, a second longitudinal reservoir formed in said rear wall substantially at the top thereof and extending in a generally'diagonally downward direction, an outlet tube connected to the upper end of said second reservoir, the other end of said serpentine tubing connected to said second reservoir substantially at the lower end thereof, a length of tubing interconnecting the lower end of said second reservoir and said chamber between the end of said inlet and-the end of said chamber wherein said inlet tube enters said" chamber, whereby liquid refrigerant will enter said inlet tube, flow through said chamber, through a portion of said serpentine tubing through and connecting in said first reservoir, through another portion of said serpentine tubing, through and collecting in said serpentine tubing'depending fromthe underside of said base, through the remainder of said serpentine tubing, when said evaporator is connected in a refrigerator, heating means mounted in thermal contact with said portion of said serpentine tubing-depending from the underside of said base for heating said portion to cause said liquid refrigerant to assume a hot gaseous state, whereby the hot gases from saidportion will be projected through said portion of serpentine tubing connected substantially to the lower portion of said second reservoir, through said length of tubing, through said chamber, and through the remainder of said serpentine tubing and said first reservoir, when said refrigerant is heated to said hot gaseous state.

7. An evaporator adapted for use and disposition wholly within acompartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically disposed rear wall attached thereto, a length of serpentine tubing formed in said base and said rear wall, a second length of serpentine tubing formed in said base and said rear wall, said second length of serpentine tubing forming a closed circuit, said second length of tubing being convoluted as to be substantially evenly spaced from said first length of serpentine tubing, an additional portion-of said second length of serpentine tubing being convoluted and formed to depend from the underside of said base, liquid refrigerant disposed within said second length of serpentine tubing, whereby said liquid refrigerant will collect'in said additional portion of said second length of serpentine tubing when said evaporator isconnected in a refrigerator, heating means mounted in thermal contact with said additional portion of said second length of serpentine tubing for heating said-additional portion to cause said liquid refrigerant'to assume a hot gaseous state, said second length of serpentine tubing further shaped so that the hot gases are projected throughout said second length of serpentine tubing when said liquid refrigerant is heated to said ho't gaseous state.

8. An evaporator'adapted for use and disposition wholly'withi'n a compartment formed in a refrigerator cabinet comprising a horizontally disposed base and a vertically" disposed rear wall attached thereto, serpentine tubingformed in said base and said rear wall, an additional portion of said serpentine tubing being formed to depend in a loopasubstantial distance-from the underside of said base, said additional portion of said serpentine tubing and said serpentine tubing being relatively arranged so that liquid refrigerant collects in said additional portion of said serpentine tubing when said evaporator is connected in a refrigerator and so that any rneans mounted in thermal contact with said additional portion for heating said additional portion to cause said liquid refrigerant to assume a hot gaseous state.

9 An evaporator adapted for use and disposition wholly within a compartment formed in a refrigerator cabinet, comprising, a horizontally disposed base and a vertically disposed rear wall attached thereto, serpentine tubing formed in said'baseand said rear wall, an additional length of serpentine tubing being convoluted so that liquid refrigerant. collects in said additional length of serpentine tubing when said evaporator is connected in a refrigerator, heating means mounted in thermal contact with said additional length of serpentine tubing for heating said additional length to cause said liquid" refrigerant to assume. a hot gaseous state, said additional length of serpentine tubing and said serpentine tubing further relatively arranged so that said hot gases are projected from one endof said additional lengthof serpentinetubing' throughout said serpentine-tubing to force any liquid refrigerant in said serpentine tubing intothe' other end of said additional length of serpentine tubing when said refrigerant is heated to said gaseous state.

References Citedin the file of this patent UNITED STATES PATENTS 2,487,662 McCloy Nov. 8, 1949 2,635,439 Philipp Apr. 21, 1953 2,654,226 Duncan Oct. 6, 1953 2,665,566 Grimshaw Ian. 12, 1954 2,665,567 King Jan. 12, 1954" 

